The invention relates generally to sailboards and more particularly to the tackle required to outhaul the sail during rigging and while sailing.
The airfoil shape of sails is set and controlled by outhaul and downhaul forces from the boom and mast. In modern sailboard rigs (sail, wishbone boom, flexible mast and universal pivot base), the primary control is downhaul force, ranging from 200 to 600 pounds. Depending on sail design, the maximum outhaul force (no wind) can range from 40 to 80 pounds and the control travel can exceed 3". Most rigs have two boomtail sheaves over which the clew line can be roved, either through the outhaul sail grommet or over sheaves in a hook block, for a 2:1 or 4:1 tackle ratio. Most rigs have the clew line anchored and cleated to the boomtail such that outhaul adjustments must be made on the beach or in the water. During the past few years, open-class racers have been running the clew line to jam cleats near their aft grip position on the booms and tying the slack ends (falls) together with elastic cords around the mast. Due to friction of small sheaves and grommet, the actual mechanical advantage of a 2:1 tackle is only 1.4:1 This means a pull range from 30 to 60 lbs, which is beyond the capability of many sailors, especially women, and tough on the hands of all.
It would be desirable to have a means to adjust the outhaul tension while sailing, especially during racing, with a control tackle apparatus which can be operated with one hand and which reduces the force to outhaul the sail by means of a mechanical advantage built into the control tackle.
Accordingly, one object of the invention is to provide an improved control tackle apparatus, which allows the sailor to more easily adjust the outhaul tension on the clew line in a sailboard rig.
Another object of the invention is to provide an improved control tackle apparatus for a sailboard rig which allows lengthening or shortening a tensioned line with one hand.